Tandem welding carriage with changeable wheel configuration and modular construction

ABSTRACT

An invention is provided which comprises a tandem welding carriage having at least two welding carriages coupled to each other. Each of the welding carriages having a base, rear wheel assemblies disposed at one end of the base, and welding attachment portions. The two welding carriages are coupled to each other using a coupling member, and each welding carriage is carrying an arc welding device and/or spool to allow for tandem arc welding.

PRIORITY

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 11/788,896 filed Jul. 17, 2007, the entiredisclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention is directed to the field of welding, morespecifically to welding carriages and tandem welding carriages.

BACKGROUND OF THE INVENTION

Large weldments benefit from automated, high deposition welding. Someapplications designed for large weldments employ large robots organtry-type positioners for moving the weld equipment into position.Other applications require the use of a travel carriage or tractor forcarrying the welding equipment.

The Lincoln Electric Co. of Cleveland, Ohio has successfully soldwelding carriages known as the LT-7 and LT-56 carriages for many years.These carriages were based upon a three-wheel design—one wheel in thefront for guiding and steering and two wheels in the rear forpropulsion. The three-wheel design tracked well because all three wheelswere in contact with the surface. The disadvantage to the three-wheeldesign was that in some joint configurations, the carriage is prone totipping.

Other manufacturers have utilized a four-wheel design. The four-wheeldesign is less prone to tipping. However, it is more difficult to createa simple steering mechanism and not all four wheels may always be incontact with the ground. Thus, the four-wheel design, like thethree-wheel design, is appropriate in certain applications, but isproblematic in others.

Both the three-wheel and four-wheel designs are adaptable to tracksystems. Track systems are used when the weld joint does not provide areliable path for guiding the carriage. Instead, one or more wheels orguides on the carriage align with the rail on the track to providedirection.

Because of the low demand for welding travel carriages, weldingequipment manufacturers generally offer only the three-wheel or only thefour-wheel carriage. Further, the cost to consumers to purchase,maintain and operate both three-wheel and four-wheel carriages hasgenerally required consumers to pick between either a three-wheel designor a four-wheel design.

Further, certain large welding applications often require multiplepasses from a single welding device to deposit a sufficient amount ofweld material to join two or more large work pieces. Current methods andequipment require these multi-pass welds to be accomplished by runningthe length of a weld with a welding carriage and then repeating theprocess multiple times with the same carriage to deposit the needed weldmaterial. This process is inefficient.

Additionally, existing welding carriages fail to provide the neededflexibility that is desired for different welding requirements.Specifically, different weldments often require different weldingequipment or a different welding equipment configuration. Thus, there isa need for a welding carriage structure to flexible in its applicationsso as to allow for the carriage to be used in a plurality of differentwelding applications with little or no modification to the carriageCurrent welding carriage manufactures attempt to address this byoffering for sale various welding carriage kits or configurations, whereeach separate kit or configuration is to be used for a particularwelding application. This solution is costly and requires the welder tostore and maintain a number of different welding kits, in addition tothe carriage assembly itself.

Accordingly, there is a need for a welding carriage which can operate inas both a three-wheel carriage and a four-wheel carriage, and one whichhas a modular construction so as to be able to be easily used in aplurality of configurations.

SUMMARY OF THE INVENTION

Various exemplary embodiments of the present invention will be discussedbelow.

An invention is provided which comprises a welding carriage having abase, rear wheel assemblies disposed at one end of the base, a firstfront wheel assembly attachment member disposed on a second side of thebase, and a first front wheel assembly configured to removably engagewith the front wheel assembly attachment member to securely couple withthe base. The welding carriage may also include a second front wheelassembly attachment member disposed on a second side of the base, and asecond front wheel assembly configured to removably engage with at leastthe at least one front wheel assembly attachment member to securelycouple with the base.

Another embodiment of the present invention contains a first weldingequipment mounting structure which is mounted to the welding carriagebase extending from an upper surface of the base, and a second weldingequipment mounting structure coupled to the first welding equipmentmounting structure. In an embodiment of the present invention, both thefirst and second welding equipment mounting structures have the samecross-sectional characteristics.

Another embodiment of the present invention contains at least a firstwelding carriage and a second welding carriage which are coupled to eachother so as to create tandem welding carriage structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages, nature and various additional features of the inventionwill appear more fully upon consideration of the illustrativeembodiments of the invention, which are schematically set forth in thefigures, in which:

FIGS. 1A through 1F are perspective views of an exemplary embodiment ofa welding carriage consistent with the present invention depicted innumerous configurations;

FIG. 2A illustrates a welding carriage according to another embodimentof the present invention;

FIG. 2B illustrates side view of the welding carriage illustrated inFIG. 2A;

FIG. 3A illustrates a cross-sectional view of one exemplary embodimentof longitudinally-movable front wheel assemblies consistent with theembodiment the present invention illustrated in FIG. 2A and FIG. 2B;

FIG. 3B illustrates a cross-sectional view of a wheel mounting armand/or equipment mounting structure in accordance with an embodiment ofthe invention; and

FIG. 4 illustrates a side view of a tandem welding carriage structure inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Disclosed is a welding carriage easily convertible between three-wheeloperation and four-wheel operation. In a further embodiment the weldingcarriage has a modular design. The present invention results in awelding carriage that can be configured in many orientations, and istherefore more flexible and versatile for users. Also, because thedesign may include many common components, it is more manufacturable andrequires fewer replacement parts for welding carriage manufactures tomanufacture and consumers to keep in stock.

With reference to FIGS. 1A through 1F, an exemplary embodiment of awelding carriage 100 consistent with the present invention will now bedescribed. FIGS. 1A-D illustrates a welding carriage 100 having a base102, a right front wheel assembly 104, a left front wheel assembly 106,rear wheel assemblies 108, front wheel assembly attachment members 110,and a welding equipment mounting member 112 (which can also be referredto as a mast). Rear wheel assemblies 108 are attached to base 102 by anyconventional or known method, such as by an axle, Rear wheel assemblies108 may be connected to drive assemblies (not shown) configured to drivethe welding carriage 100 by causing the rear wheel assemblies to rotate.

Control of the movement of the welding carriage 100 is by anyconventional known method or means. For example, it is contemplated thatthe carriage 100 be controlled automatically via a computer controlsystem, or manually as needed. The present invention is not limited inthis regard.

Attached to base 102 are front wheel assembly attachment members 110.Front wheel assembly attachment members 110 are configured to couplewith attachment ends 104 a, 106 a of right front wheel assembly 104 anda left front wheel assembly 106. Namely, the attachment members 110 areused to removably couple the assemblies 104, 106 with the base 102.

The coupling or attachment between front wheel assembly attachmentmembers 110 and attachment ends 104 a, 106 a of right front wheelassembly 104 and left front wheel assembly 106 securely hold the rightfront wheel assembly 104 and/or the left front wheel assembly 106 to thebase 102 during operation of the carriage, while allowing efficientremoval of the right front wheel assembly 104 and/or left front wheelassembly 106 when needed. Each of the attachment members 110 are securedto the base by any known or conventional used means, and are made of anyconventionally known material.

In an embodiment of the invention, the attachment members 110 areconfigured such that they allow for the removable attachment of thewheel assemblies 104/106 in an interchangeable and flexible fashion.Specifically, as shown in FIGS. 1B and 1C the wheel assemblies 104/106are interchangeable between the left and right side of the base 102.Additionally and alternatively, the wheel assemblies 104/106 can bemounted in such a way where the wheel is extending out away from acenterline of the base 102 or can alternatively be mounted such that thewheel is extending toward the centerline of the base. This can be seenin FIGS. 1B and 1C, for example.

In an embodiment of the invention, the wheel assemblies 104/106 aresecured to the attachment members 110 with a quick release or pressuretype fit, such that the wheel assemblies 104/106 are secured during useof the carriage 100, but can be easily removed or reconfigured withminimal effort. Examples include, quick release pins, spring-activatedpins or fasteners, screws, bolts, or the like.

As shown in FIG. 1F, the right front wheel assembly 104 and left frontwheel assembly 106 each include an attachment end 104 a, 106 a, asupport arm 104 b, 106 b, and a wheel 104 c, 106 c. The right frontwheel assembly 104 and the left front wheel assembly 106 are designed toallow for multiple welding configurations, and interchangeability on thewelding carriage assembly 100. The present invention is not limited bythe material or cross-sectional aspect of the assemblies 104/106.However, common materials may be used for the components of the wheelassemblies 104/106, and should be selected, at least in part, based onthe environment on which the welding carriage 100 will be operated.

It is further noted that although FIGS. 1A through 1F depict the wheelsas being positioned off-center from the support arms 104 b/106 brespectively, the present invention is not limited to thisconfiguration. In an alternative embodiment of the present invention,the wheels 104 c/106 c are positioned along the centerline of the arms104 b/106 b. The present invention is not limited in this regard, nor isit limited with regard to how the wheels 104 c/106 c are mounted to thesupport arms 104 b/106 b.

The following discussion will now turn to each of FIGS. 1A through 1Frespectively and provide an explanation of the aspects of the presentinvention shown in each Figure.

FIG. 1A illustrates an embodiment of a welding carriage 100 in afour-wheel configuration. Here, both the right front wheel assembly 104and the left front wheel assembly 106 are attached to the base 102 withthe front wheel 104 c, 106 c directed outward from the centerline of thebase 102. Also, a mounting member (i.e. mast) 112 is coupled to the body102 so as to permit the mounting of additional welding equipment, whichwill be discussed in more detail below. Further, although the traveldirection is indicated as from the rear wheels 108 toward the wheels 104c/106 c, the present invention is not limited in this way, and thecarriage 100 can be moved in either direction depending on theoperational needs for any particular welding operation.

FIG. 1B illustrates another embodiment of the welding carriage 100 in afour-wheel configuration with both the right front wheel assembly 104and the left front wheel assembly 106 having their front wheels 104 c,106 c facing the same direction. Although in this figure the wheels arefacing to the left of the carriage 100, the invention is not limited inthis regard as the wheels can be easily switched to face the oppositedirection, depending on the application and environment on which thecarriage assembly 100 is being used.

FIG. 1C illustrates another embodiment of the welding carriage 100 in athree-wheel configuration with only the left front wheel assembly 106attached to the base 102. Here, the left front wheel assembly 106 isattached to the base 102 in such a manner that the front wheel 106 c isdirected inward. Of course, because of the nature of the invention, theassembly 106 can be switched so that the wheel 106 c is facing outboard.Further, rather than the left wheel assembly 106, the right wheelassembly 104 may also be used in a similar manner.

FIG. 1D illustrates another configuration of the welding carriage 100 ina three-wheel configuration with only the right front wheel assembly 104attached to the base 102. Here, the right front wheel assembly 104 isattached to the base 102 in such a manner that the front wheel assembly104 c is directed outward. Of course, because of the nature of theinvention, the assembly 104 can be switched so that the wheel 104 c isfacing inward. Further, rather than the right wheel assembly 104, theleft wheel assembly 106 may also be used in a similar manner.

FIG. 1E illustrates the base 102 without either the right front wheelassembly 104 or the left front wheel assembly 106 attached.

FIG. 1F illustrates a front wheel assembly 104, 106. As shown, theassemblies 104/106 have an attachment end 104 a, 106 a which is the endcoupled to the attachment members 110, to secure them to the base 102.The support arm 104 b, 106 b extends from the attachment end 104 a/106 aso as to locate the wheel 104 c, 106 c, some distance remote from theattachment end 104 a/106 a. The present invention is not limited to thespecific embodiment shown in this figure as the wheel assemblies 104/106can be configured in any number of ways such that the present inventionis achieved.

In the exemplary embodiment illustrated in FIG. 1A through FIG. 1F, thefront wheel attachment member 110 is a generally channel-shaped memberdesigned to engage a pair of recesses on the attachment ends 104 a, 106a of the front wheel assemblies 104, 106. The front wheel attachmentmembers 110 and the attachment ends 104 a/106 a are not, however, solimited and can have any number of configurations. However, the frontwheel attachment members 110 and the attachment ends 104 a/106 a allowfor the wheel assemblies 104/106 to be efficiently removed andreposition on the base 102.

In an embodiment of the present invention, the wheel assemblies 104/106are identical such that either could be used on either the left and/orright side of the carriage 100 interchangeably. In such an embodiment,the wheel assemblies 104/106 are not specifically designed for the rightor left side of the carriage 100. Such an embodiment increases theworkability and flexibility of the carriage 100.

Turning now to FIGS. 2A and 2B, a further embodiment of the presentinvention will now be discussed. FIGS. 2A-B illustrate an additionalexemplary embodiment of a welding carriage consistent with the inventiondisclosed in this patent application.

In the exemplary embodiment of FIGS. 2A-B, a welding carriage 200includes a base 202, right front wheel assembly 204, left front wheelassembly 206, rear wheel assemblies 208, mounting arm attachment members210, welding equipment mounting member (mast) 212, and a front wheelassembly mounting arm 214. The base 202 may also include a motor anddrive assembly (not shown) for propelling the welding carriage bycausing the rear wheels of the rear wheel assemblies 208 to rotate.Additionally, a second equipment mounting member 218 is coupled to theequipment mounting member 212 with an attachment portion 220.

In an exemplary embodiment of FIGS. 2A and 2B, front wheel assemblies204, 206 may be longitudinally moved relative to one another in thedirection of travel of the welding carriage 200. The wheel assembliesmay also be configured to allow for inboard and outboard positioning ofthe wheels of the front wheel assemblies 204, 206 (similar to that shownin FIGS. 1A to 1D). Thus, as illustrated in FIG. 2A, left front wheelassembly 206 is positioned ahead of the right front wheel assembly 204.Many other arrangements can, of course, exist. For example, the wheels204 c/206 c can be positioned such that they are directed away from thecenterline of the carriage 200, at the centerline, or some combinationthereof, This is illustrated in the embodiments shown in FIGS. 1Athrough 1D. Further, the wheels 204 c/206 c can be positioned the samedistance from the base 202, or at some alternating distances as shown.The configuration of this embodiment of the present invention allows forthis flexibility.

To allow the front wheel assemblies 204, 206 to be longitudinally movedon front wheel assembly mounting arms 214, the front wheel assemblies204, 206 include an attachment portion 222. The attachment portion 222secures the wheels 204 c/206 c to the arms 214. An embodiment isillustrated in FIG. 3A which shows the attachment portion 222 securingthe wheel 204 c to the arm 214. As shown in this embodiment a clamp typestructure is used for the portion 222 to secure it to the arm 214. Thusthe attachment portion 222 contains a wheel mounting portion 222 b, asecuring portion 222 a and a securing mechanism portion 222 c. The wheelmounting portion 222 b secures the wheel 204 c to the remainder of theattachment portion 222 and allows the wheel to rotate during operation.The securing portion 222 a secures the attachment portion 222 to the arm214 by encompassing the periphery of the arm 214. The securing mechanismportion 222 c is used to provide the securing force to secure theattachment portion 222 to the arm. For example, in the embodiment shownin FIG. 3A the securing mechanism portion 222 c employs a compressionforce to provide a frictional engagement between the arm 214 and theportion 222, so as to prevent movement.

When the compression force is removed, the attachment portion 222 can bemoved along a length of the arm 214 to adjust the relative position ofthe wheel. Additionally, it is contemplated that in an embodiment of theinvention, not only can the attachment portion 222 be movedlongitudinally along the arm 214 but it can be rotated on the arm 214.Such rotation allows the wheel 204 c to be placed at any desired anglefor operation of the carriage 200. For example, if the carriage is to beoperated on an angled surface, the wheels can be angled accordingly.

Although not shown in FIG. 3A, it is also contemplated that the arm 214has a groove or a series of grooves (alternatively a protrusion or aseries of protrusions), which engage with correspondinggrooves/protrusions in the securing portion 222 a. Thegrooves/protrusions provide a locking effect to assist in preventrotation or unintentional movement of the attachment portion 222 duringoperation.

It is noted that even though an embodiment of the attachment portion 222is shown in FIGS. 2A and 3A, the present invention is not limited tothis embodiment. It is understood that it is well within the skill ofthose of ordinary skill in the art that many different attachmentportions or mechanisms can be used to secure the wheels 204 c/206 c tothe arms. It is further understood that any known and conventional meansor methods can be used to accomplish this, while at the same timeallowing for easy movement and alteration of the wheel location alongthe arm. For example, a spring loaded securing mechanism can be used, apin or fastener securing mechanism can be used, a tensioning typemechanism can be used, etc. The present invention is not limited in thisregard, and the configuration shown in the Figures is only intended tobe an illustrative embodiment and does not limit the present inventionin any way.

Of course, any known or conventional used materials can be used for theabove discussed components and are to be selected based on at leastoperational, design and environmental concerns.

Further, although FIGS. 2A and 3A show the attachment portion 222 usinga fastener 222 d to provide the fastening force, the present inventionis not limited in this regard. Further, the fastener 222 d can be anyone or, or combination of, commonly used fasteners, including but notlimited to snaps, nuts and bolts, pins, clevises, springs, quick releasepins, or the like.

The mounting arms 214 are securely coupled to the welding carriage base202. In one embodiment, mounting arms 214 are attached to the base 202by mounting arm attachment members 210, which can comprise any number ofwell known structures. Alternatively, front arm mounting arms 214 can bewelded to base 202, molded into base 202, or otherwise coupled with base202 in any number of known manners. In a further embodiment, the arms214 are slidably engaged with any one of the base 202 or the mountingmembers 210, or a combination of both. In such an embodiment, the arms214 can be slid further into or out of the base 202 to adjust theirlength. Therefore, with such an embodiment, if it desired to reduce theoverall length of the carriage 200, without employing different arms214, the arms can be slid into the base 202, without requiring cuttingor replacement of the arms 214.

In the embodiment illustrated in FIGS. 2A, 2B and 3A, the front armmounting arms 214 are generally circular in cross section. However, theinvention is not so limited. The front arm mounting arms 214 can be,inter alia, bar-shaped, oval-shaped, square-shaped, or polygonal-shaped.The present invention is not limited in this regard. Further, the arms214 can be hollow or solid material.

Thus, as with the previously discussed embodiment, a welding carriageconsistent with the embodiment illustrated in FIGS. 2A and 2B canoperate in three-wheel of four-wheel mode. Further, in both three-wheelof four-wheel mode, the front wheels can have multiple orientations(inward or outward) and can be positioned in many positionslongitudinally and/or radially along the length of mounting arms 214.

FIG. 3B depicts a cross-section of an exemplary embodiment of the arm214 in accordance with an aspect of the present invention, The arm 214has a plurality of grooves 214 a which radially extend inward from anouter surface 214 b of the arm 214. As discussed above, the grooves 214a are employed to interlock with corresponding protrusions in theattachment portion 222 (not shown) to secure the assembly 204/206 duringoperation. The present invention is not limited with regard to the shapeor number of the grooves. For example, it is contemplated that in oneembodiment there is a single locking groove/protrusion, while in anotherembodiment there are many grooves/protrusions. Further, the presentinvention is not limited with regard to the dimensions andcross-sectional shapes of the grooves 214 a. Further, it is contemplatedthat in an alternative embodiment a series a protrusions (not shown) canbe employed which extend radially outward from the surface 214 b of thearm 214 to engage with corresponding grooves in the attachment portion222. It is further contemplated that the arm 214 can have anycombination of grooves and protrusions within the surface 214 b of thearm 214 to interact with the attachment portion 222. Further, althoughthe embodiment shown in FIGS. 2A and 2B depict grooves which runlongitudinally along the entire length of the arm 214, the presentinvention is not limited in this regard as the grooves/protrusions canrun radially or have a discontinuous nature. It is further contemplatedthat dimples, or the like can be used on the arm 214.

As shown in FIGS. 2A and 2B a welding equipment mounting member 212 (ormast structure) extends vertically from the base 202. The mountingmember 212 is employed to mount various pieces of welding equipmentwhich is to be carried along with the carriage 200 during a weldingoperation. In one embodiment of the present invention, the weldingequipment is mounted directly to the mounting member 212. However, asshown in FIGS. 2A and 2B a second equipment mounting member 218 issecured to the mounting member 212. As shown in FIGS. 2A and 2B thesecond mounting member 218 (or crossbar) is mounted perpendicular to themounting member 212. However, the present invention is not limited inthis regard as either the mounting member 212 can be mounted at an angleother than 90 degrees to the surface of the base 202, and the secondmounting member 218 can be mounted at an angle, other than 90 degrees,to the mounting member 212.

In an embodiment of the invention, both the mounting member 212 and thesecond mounting member 218 have the same outer cross-sectionalcharacteristics. This is done to allow for interchangeability andflexible operation of the carriage 200 in multiple welding applications,without the need for different mounting structure. Of course, eventhough a single second mounting member 218 is shown in FIGS. 2A and 2B,the present invention is not limited in this regard as more than onesecond mounting members may be mounted to the mounting member 212.

The second mounting member 218 is configured to allow for variouswelding devices or equipment to be coupled to the member 218. Forexample, as depicted an electrode spool 216 may be mounted to the member218. The present invention is not limited in this regard as manydifferent types and kinds of welding equipment can be mounted to eithermounting member 212/218.

The mounting member 212 is secured to the base 202 with an attachmentportion 224. The attachment portion 224 can be of a similar constructionto that of the attachment members 210 or the portion 222, or be of thegenerally same construction. In an embodiment of the invention, theattachment portion 224 is of a type which allows the mounting member 212to be raised or lowered vertically and/or be rotated about its axis.Such an embodiment maximizes the flexibility and usability of thecarriage 200.

The second mounting member 218 is coupled to the mounting member 212with another attachment portion 220, of similar construction andfunction as the previously discussed attachment portions. In anembodiment of the invention, the attachment portion 220 is of aconstruction which allows either of the mounting members 212/218 to berotatable within the attachment portion 220, and/or longitudinallymovable within the attachment portion 220. In an embodiment of theinvention, the attachment portions 220 and/or 224 are of a constructionto allow the easy change from one configuration to another. For example,in an embodiment the attachment portions have a similar construction andoperation as the portion 222, described above, the discussion of whichis incorporated here by reference.

Further, the electrode spool 216 (or any other welding equipment) ismounted to the members 212/218 with a similar type attachment portion,to provide additional flexibility in operation and configuration. Thisallows the attached welding equipment (for example the spool 216) to beable to be moved longitudinally along the length of the portion 218, aswell as be rotated on the portion 218.

In a further embodiment of the present invention, the mounting members212/218 have the same outer cross-sectional characteristics as the arms214. This is to maximize operational flexibility and efficiency, as thecomponents become interchangeable, and allow for ease of maintenance andstorage of replacement components. It is further contemplated that thevarious attachment portions employed by the present invention aresimilar in structure so as to maximize product flexibility andefficiency, as well as minimize costs for replacement parts andmaintenance.

Examples of components which can be mounted on either of the mountingmembers include: wire reel spindles, flux hoppers, wire drives,pendants, control boxes, pre-heat torches, laser tracking devices,vision tracking devices, etc.

Also shown in the embodiment of FIG. 3A is a key portion 226. In theshown embodiment the key portion 226 engages with the grooves 214 a ofthe arm 214 such that when the attachment portion 222 is loosed (toallow movement) the attachment portion 222 does not uncontrollablyrotate around the arm 214. Of course, although this figure shows the arm214 for the wheel assemblies, this similar configuration can be used onthe mounting members 212/218, as the mounting of components is similarin nature, and can be the same, between the wheel mounting structure andthe welding equipment mounting structure, It is contemplated that duringthe use of the present invention the wheel, welding component orapparatus (such as, for example, the electrode spool 216) which issecured to the arm 214 or portions 2121218 is not balancedsymmetrically. When this is the case, and the attachment portion 222 isloosened the portion 222 can be caused to rotate, thus causing injury ordamage. The key portion 226 is secured to the attachment portion 222 andengages with groove 214 a to prevent such rotation. It is noted that inan embodiment of the invention, the grooves 214 a may also similarlyexist in portions 2121218. The key portion 226 is to be of a length,dimension and configuration such that inadvertent rotation of a wheelassembly or mounted welding component can be prevented Any commonlyknown or used material may be employed. Although a plate-likeconfiguration is shown for the key portion 226 of the shown embodiment,the present invention is not limited in this regard. It is contemplatedthat any type of commonly known or used key portion or locking mechanismcan be employed to prevent inadvertent rotation. Additionally, in afurther embodiment of the present invention the key portion 226 is notcoupled to the attachment portion 222 and is separately located alongthe arm 214 or portions 212/218 to provide an anti-rotational effect. Ina further embodiment, the key portion 226 is movably engaged with theattachment portion 222 (or with its own mounting mechanism in suchembodiments where the key portion 226 is not coupled to the attachmentportion 222) such that it can be released from engagement with thegrooves 214 a to permit rotation when desired. Any commonly known orused mechanism or configuration can be used to provide the movableengagement. For example, the key portion 226 can be provided with anurging force (such as that provided by a spring or similar device) whichurges the key portion 226 into the grooves 214 a, but also allows thekey portion 226 to be withdrawn from the grooves 214 a when an oppositeforce is applied which is larger than the urging force. The presentinvention is not limited in this regard.

FIG. 4 depicts of a further embodiment of the present invention.Specifically a tandem welding carriage 400 is shown. In this embodiment,two welding carriages 200 are coupled to each other using couplingmembers 405. Coupling members 405 are similar in structure to arm 214and are interchangeable with arm 214 so that the attachment members 210can be used. This greatly increases the flexibility of the weldingcarriages of the present invention. Specifically, it is contemplatedthat, as needed, an operator can employ two separate welding carriages200 of the present invention and securely couple them to each other withmembers 405 to create an tandem welding carriage 400 as shown.

As discussed previously, many welding applications require multiple weldpasses to provide a sufficient weld. The tandem welding carriage 400simplifies these welding processes by providing a moveable carriageplatform which allows for at least two welding arcs to be employed onthe same carriage structure, moving together along the weld.

With the modular structure of the present invention, a user can easilycoupled two welding carriages 200 to create a tandem welding carriage400 carrying two arc welding devices 401 and welding tips 403. The arcwelding devices 401 and welding tips 403 are of any conventional knownor used configuration and the present invention is not limited in thisregard.

The movement of the carriage 400 (using the carriages 200) is similar tothat described above. Specifically, in an embodiment of the inventionthe wheels 208 of either the leading carriage 200 or the trailingcarriage 200 provide the movement of the carriage 400. The drive of thewheels 208 can be by any conventional means, including a drive motor(not shown) within the carriage 200. Further, control of the speed, etc.of the wheels 208 can be done by any conventional means, such ascomputer control via a preprogrammed CPU, or the like, throughprogramming via a pendant or wireless control or manually via anyconventional means, such as a pendant.

In an embodiment of the invention, when the carriages 200 are coupled toeach other as shown to create the tandem welding carriage 400 one of thecarriages 200 becomes the master carriage, or drive carriage, and theother becomes the slave carriage, or the following carriage. Forpurposes of the present invention it is irrelevant whether or not themaster carriage is the lead carriage in the travel direction or not. Inan example, an operator can designate, via any input means ormethodology, which carriage will be the master or drive carriage andwhich will be the slave carriage. Alternatively, it is contemplated thatthe carriages 200 can be electrically coupled to each other (via a wiredor wireless connection) such that the carriages can communicate witheach other and through a simple logic program determine automaticallywhich carriage is to provide the drive force to the tandem carriage 400.

For example, in looking at FIG. 4, if the travel direction of the tandemcarriage 400 is to be to the right of the figure, the logic internal tothe carriages 200 (or alternatively any control mechanism such as apendant or computer controller) determines that the carriage 200 to theright (i.e., the lead carriage) will be the carriage providing the driveforce. Then as the travel direction changes, the logic/control mechanismwill change the driving carriage 200 to the carriage on the left of thefigure. Alternatively, in an embodiment, the drive carriage 200 will notchange as in many applications it may not be important as to whichcarriage is the driving carriage.

In a further embodiment, it is contemplated that both carriages 200provide the drive force to their respective wheels 208. In such anembodiment, the operation of the carriages 200 should be synced suchthat the carriages 200 are not competing with each other regarding thedesired path, speed, motion, etc. Those of skill in the art wouldunderstand how to implement such a control system.

In an embodiment, each of the carriages 200 is controlled from and/orreceives power from a single control/power source (not shown).Alternatively, it is contemplated that the respective carriages 200receive their power/control from separate control/power sources.

As shown in FIG. 4, each carriage 200 has an arc welding device 401mounted on their respective equipment mounting member 218, such that thearc welding devices are positioned near to each other. Such aconfiguration allows for a single carriage structure to deposit twice asmuch weld metal as prior art single arc welding carriages. This isbeneficial in welding applications such as sub-arc and GMAW. Because ofthe flexibility of various embodiments of the present invention, weldingoptimization is achieved.

For example, as shown in FIG. 4, the arc welding devices 401 arepositioned in line with each other longitudinally (i.e., in the traveldirection). However, the present invention is not limited in thisregard. In fact, with the flexibility of the present invention, in oneembodiment the arc welding devices 401 and/or welding tips 403 arepositioned so that they laterally next to each other (i.e., normal tothe travel direction). Additionally, because of the flexibility of thepresent invention as described above regarding the equipment mountingmembers 212 and 218 (rotationally, vertically, etc.), the welding tips403 can be configured in any desirable way to perform the needed weldingprocess. For example, the tips 403 can be angled with respect to eachother and the carriages 200, or they can be staggered such that theirrespective welds do not overlap. In an embodiment of the presentinvention, the carriages 200 are fixed to each other such that thelinear spacing between the tips 403 is between about ½″ to about 6″.

It is contemplated that the welding power/waveform for each of therespective arc welding devices 401 is provided from individual powersupplies, respectively. Of course, to the extent that a power supply cansupply separate welding waveforms to the devices 401, then a singlepower supply can also be used.

In another embodiment of the present invention, an extra wheel(s) 204c/206 c can be placed on the coupling members 405 to provide addedsupport, depending upon the length between the carriages. Further, thecoupling members 405 can be of a type having an adjustable length, suchas with a telescoping structure, thus adding to the flexibility of thecarriage 400 by permitting the spacing to be adjustable depending on thespecific needs of the welding operation to be performed.

In a further exemplary embodiment, rather than using two couplingmembers 405 a single coupling member 405 can be used to secure thecarriages to each other, provided that the coupling member 405 has thedesired structural integrity to join the carriages 200. In the place ofthe other coupling member, a wheel assembly or assemblies (for example,as shown in FIGS. 2A and 2B) can be mounted to provide additionalstability, if needed. Further, this configuration can be employed when agap is needed between the carriages 200 because of a welding operation,etc. Therefore, only one side of the space between the carriages will bea coupling member 405, while on the other, wheel assemblies will be usedto provide a needed gap.

In a further embodiment of the present invention, a hinge structure 407is positioned on the coupling members 405. The hinge structure 407 canbe of any known or conventional used configuration to allow the carriage400 to travel around corners and/or up hills. In an embodiment the hingestructure 407 is a single axis hinge structure, while in anotherembodiment the hinge structure 407 can be a u-joint or ball-typestructure which provides for multiple degrees of freedom. As shown inFIG. 4, a single hinge structure 407 is shown on the member 405.However, it is contemplated that other embodiments of the presentinvention will have more than one hinge structure 407 on the members405. In yet a further embodiment of the present invention, the hingestructure 407 can be of a type which can be made mechanically rigidtemporarily, such as through a locking pin, or the like. In thisembodiment, there is no need to replace the members 405 when switchingfrom an operation requiring a hinged member 405 to one requiring a rigidmember 405, and vice versa. Simple unlocking or locking of the hingestructure 407 allows the member 405 to be made rigid or flexible asneeded. One of ordinary skill in the art is familiar with known methodsto provide a locking mechanism to the hinge structure 407.

In a further alternative embodiment, rather than having the hingestructure 407 along the span of the member 405, the hinge structure 407can be located at one, or both, ends of the member 405 such that theconnection to the carriages 200 is hinged, allowing a pivoting orrotational movement at the interface with the carriages 200 as opposedto along the span of the member 405. Of course, multiple hinges atmultiple points along the member 405 is contemplated and placementshould be optimized based on operational needs and desired flexibilityof the carriage assembly 400.

To optimize the flexibility of the present invention, in an embodimentof the cross-section of the coupling member 405 is the same as that usedfor the other members of the carriages 200. For example, thecross-section of the coupling member 405 is the same as on the members212, 218 and even the wheel mounting arms 214. This commonality allows auser to configure and reconfigure the carriage assembly 400 as neededwhile requiring minimal replacement or additional parts.

In a further exemplary embodiment of the present invention (not shown),one carriage 200 can carry both arc welding devices 401, while the othercarriage 200 can carry both electrode spools 216. In such an embodiment,the arc welding devices can be positioned such that they are bothleading or following the entire tandem carriage assembly 400. Of course,because of the flexibility of the present invention, other embodimentsare contemplated. For example, in a further alternative embodiment,three carriages 200 are secured to each other where one carriage 200carries three arc welding devices 401 and the remaining two carriages200 carry the spools 216. Further, two carriages 200 can carry the arcwelding devices 401 and spools 216 while a third carriage 200 carriesother equipment that may be needed or desired for a specific weldingoperation.

Further, because of the flexibility offered by the present invention,more than two carriages 200 can be coupled together to create a tandemwelding carriage 200 with more than two (2) arc welding devices 401. Thecoupling between multiple carriages 200 would be similar to that shownand discussed above and will be discussed in detail again.

One of the benefits of the present invention lies in the fact that oncea tandem welding operation is completed, the carriage 400 can beseparated into its respective individual carriages 200, thus allowingfor single carriage welding to be performed.

Of course, it is contemplated that the welding carriages disclosed inthis application can be configured in any way such that the spirit ofthe invention is maintained, and the invention is not limited to theexemplary embodiment discussed above.

The present invention has been described with certain embodiments andapplications. These can be combined and interchanged without departingfrom the scope of the invention as defined in the appended claims. Theinvention as defined in these appended claims are incorporated byreference into the specification of this application as if part of thedescription of the novel features of the present invention.

1. A tandem welding carriage comprising: at least two welding carriages,each welding carriage comprising: a base, at least two wheels disposedat one end of the base; a first wheel assembly attachment memberdisposed on another end of the base; and a second wheel assemblyattachment member disposed on said another end of the base; at least onecoupling member which couples said at least two welding carriages toeach other, where a first end of said at least one coupling member issecured to either of said first or second wheel assembly attachmentmember on one of said welding carriages and a second end of said atleast one coupling member is secured to either of said first or secondwheel assembly attachment member on the other of said welding carriages;wherein said at least one coupling member is removably engaged with eachof said wheel assembly attachment members to which it is secured.
 2. Thetandem welding carriage of claim 1 further comprising a second couplingmember removably secured to the other of said first and second wheelassembly attachment member on said one of said welding carriages and theother of said first and second wheel assembly attachment member on theother of said welding carriages.
 3. The tandem welding carriage of claim1, wherein said at least one coupling member comprises a hinge structurewhich allows at least a portion of said at least one coupling member tobe pivotally or rotatably secured to at least one of said weldingcarriages.
 4. The tandem welding carriage of claim 1, wherein each ofsaid welding carriages further comprises at least one welding equipmentmounting member.
 5. The tandem welding carriage according to claim 1,wherein said at least one coupling member comprises a wheel structurepositioned between each of said at least two welding carriages.
 6. Thetandem welding carriage according to claim 1, wherein at least one wheelassembly is removably secured to the other of the first and second wheelassembly attachment member on at least one of said welding carriages. 7.The tandem welding carriage according to claim 4, wherein said at leastone coupling member has the same outer cross-section of at least one ofsaid welding equipment mounting members.
 8. The tandem welding carriageaccording to claim 1, wherein only one of said at least two carriagesprovides a drive force for said tandem welding carriage.
 9. The tandemwelding carriage according to claim 1, wherein an arc welding device ismounted to each of said at least two welding carriages and each of saidarc welding devices are oriented to be adjacent to each other.
 10. Atandem welding carriage comprising: at least two welding carriages, eachwelding carriage comprising; a base, at least two wheels disposed at oneend of the base; a first wheel assembly attachment member disposed onanother end of the base; and a second wheel assembly attachment memberdisposed on said another end of the base; at least two coupling memberswhich couple said at least two welding carriages to each other, where afirst end of each of said coupling members is secured to either of saidfirst or second wheel assembly attachment member on one of said weldingcarriages and a second end of each of said coupling members is securedto either of said first or second wheel assembly attachment member onthe other of said welding carriages; wherein each of said couplingmembers is removably engaged with each of said wheel assembly attachmentmembers to which it is secured.
 11. The tandem welding carriage of claim10, wherein each of said coupling members comprise a hinge structurewhich allows at least a portion of each of said coupling members to bepivotally or rotatably secured to at least one of said weldingcarriages.
 12. The tandem welding carriage of claim 10, wherein each ofsaid welding carriages further comprises at least one welding equipmentmounting member.
 13. The tandem welding carriage according to claim 10,wherein at least one of said coupling members comprises a wheelstructure positioned between each of said at least two weldingcarriages.
 14. The tandem welding carriage according to claim 12,wherein each of said coupling members has the same outer cross-sectionof at least one of said welding equipment mounting members.
 15. Thetandem welding carriage according to claim 10, wherein only one of saidat least two carriages provides a drive force for said tandem weldingcarriage.
 16. The tandem welding carriage according to claim 10, whereinan arc welding device is mounted to each of said at least two weldingcarriages and each of said arc welding devices are oriented to beadjacent to each other.